The remaining 128 characters can be used for coding the special national language characters. There are for example the characters á, č, ü, etc., used for Central European languages and ф, и, б, ъ, etc. characters used in the Russian. Unfortunatelly the number of these special national language characters is too high, therefore all of them cannot be coded using the remaining 128 resources. That is why the special code pages has been created for different national language groups. For example, the Win-1250 codepage used for the Central European languages, the Win-1251 codepage containing all Cyrillic alphabet characters, etc. This way it was possible to save international language texts, but it was not possible to combine the characters of different codepages into one text file.
The main advantage of UTF-16 is a very simple management of all possible characters, the disadvantage is the double size and ASCII table incompatibility. The incompatibility problem is considerable when text files are being saved. Therefore the alternative Unicode coding system has been created, which is operating with variable lenght of the saved character. The ASCII table characters are stored into 1 byte, while the non-ASCII characters are stored into 2 or more bytes (the 1st byte contains the information whether another byte is following). This coding system is branded UTF-8. It is mainly used for text (XML, HTM) files. While working with such texts, the characters are transformed into UTF-16 in the computer´s operating memory, making it work faster this way.